Tool for drilling concrete, etc.



1,629,581 May 24. 1927. A' w'- MACHLET r TOOL FOR DRILLING CONCRETE, ETC

Filed Oct. 27, 1923 "GGG-@QU /n venfor:

O :Afram'y Patented May 24, i927.

.UNITED STATES YParlant OFFICE.,

ADOLPH L` MACI-ILET, F ELIZABETH, NEW JERSEY.

TOOL FOR DRILLING CONCRETE, ETC.

Application filed October 27,1923. Serial No. 671,086.

anchorage and other purposes, as for example in installing hangers, shelves and sinks, i

and in fastening machinery to the floor.

In drilling such holes, it is the custom to use achisel like toolor bit which is crosspointed or ycross-shaped vin transverse section at the nib, and it has to be turned during the operation of hammering or pounding it into the cement or other material to grind upv the material and make a round hole. All of the material that comes from the hole is first pounded or ground into powder by such a tool, entailing much labor and loss of time and consumption of power. The usual drills tend to make irregularly shaped holes, and in operatingthem care and skill must be exercised, as otherwise the drill will lock itseli1 against turning, and is apt to produce an irregularly shaped hole instead of a round one.

The tools are expensive to make in comparison to the small amount of service which they can render. They rapidly wear away, necessitating frequent resharpening, and soon have to be discarded. Moreover, the

corners of the cross-shaped tool wear away in a Ashort time, thus changing the diameter of the hole, so that the holes successively produced by thesame tool are less and less in diameter; and it becomes necessary, therefore, for a workman to provide himself withmany duplicate tools in order to preserve as nearly as possible uniformity of diameter of holes.

The holes produced by common methods arenot uniformly circular, but are usually of irregular contour.V The interior of the hole is apt to be irregular also, even where the top of the hole may look round and satisfactory. The-result is that the expansion bolt when placed in the hole has a poor hold and is not adequately supported throughout the length of the hole, because of its irregular and hollowed-out interior.' This is a source of annoyance and weakness and is otherwise objectionable. Y

Moreover, it is found diiiicult to make a hole that shall be'within the required limits as to diameter. The expansion bolt itself is capable of only slight. expansion, and

when placed in the hole it is sometimes found that the bolt will not expand enough to become anchored, on account of the oversize of'the hole. A closely fitting holeis demanded. If the diameter of the hole is beyond the range of expansion of the bolt, the taper therein will pull through.

The closer the hole is tothe expansion bolt the better.v The diameter of the bolt must match the diameter ofthe hole. There must be uniform diameter of the hole and uniform fit throughout its depth. EXpansion bolts have a limited range of expansion, of from g to 1/8 of an inch, and owing Ato this small range it results that if the hole in the concrete is rough, the -bolt cannot be satisfactorily tightened and anchored in the hole.'

Y To overcome the difficulties and meet the requirements, the present invention is in the nature of a hollow cylindrical bit or tool having a self-renewing wearing edge or nib and embodying a provision for securing clearance and assuring accurate and true form of the hole in the cement or the like for its entire depth. 'n

Other features and advantages will hereinafter appear. y

In the accompanying drawings,

Figure 1 shows an elevation of one form of drill of the class specified.

Figure 2 is a cross-section.

Figure 8 is an end view of the same showing the nib or cutting edge in its original condition. v

Figure l is lsimilar-to Figure 3, but shows a drill having internal teeth or ribs, as well as the external teeth or ribs seen at Figure 3.

Figure 5 'isa view similar to Figure 2, but showing also the internal teeth or ribs of Figure 4.'

Figure 6 is a view similar to Figure l, but shows a smaller tool having fewer sides and ribs.

Figure 7 is an end view of the tool seen at Figure 6. l

Figure 8 is similar'to Figure 7, but shows also the internal teeth or ribs. I

Figures 9 and 10 show a point secured to the drill for starting the hole in the work; the same being shown in sectional and end views. v v

The improved hollow tool l0 is cylindrical and is longitudinally fluted at ll all around the tool, and. the longitudinal ridges 12 which are formed by the iiuting have the appearance of projecting teeth or spurs, when the .tool is viewed. in cross-section,

always free therein.

Figure 2. The fluted portions of the cylinder are formed with longitudinal rows of perforations 13, which are illustrated as circular, although not limited to circular form. Til/'ith the end or nib 11i of the tool placed against the cement or other work 15, the tool is hammered or wor cd as a drill, and the edge of the cylinder, forming the nib 14;, serves to grind away or break up the cement or other material, and to produce an annular cut 16, 17 in said material, the cut proceeding to the desired depth, and being cylindrical thror rhout its depth, since the tool is of uniform dian'zeter from end to end; and a solid or uncut core .18 is left in the hole, which core lnoken off and removed, either at the coiupletion of the drilling or from time to time during its progress. The tool makes a fine, true hole. instead of pounding or grinding up all of the material to be removed from the hole, this tool only grinds up the annular space 16, 17, in which tie tool works, leaving the Core which can be removed in solid condition.

'lhe perforations in the liutings 11` have the eliect of producing gaps 1?) in the selfrenewing nib or working end or edge of the hollow tool, Figure These perforations areV stagggered, Figures 1 and 6, so that, as the tool wears away, the constant-ly changing woi'l-:ing-edge or nilo 1l remains substantially uniform in are l and efliciency, requiring substantially uniforn'i handling or pounding, and proceeds at substantially uniform speed through the work. During the hammering operation, the drill, in certain classes of work, may be rotated slightly, as to make a complete annular channel 16, 17 in the work.

The radiating` or projecting teeth 12 seen on the end of the tool are eiiicient in secury clearance for the tool in the work, so

there is no liability of the tool becoming frozen or caught in the work., but it is The ribs 12 may be even relatively closer than illustrated, so that the tool may hammered into the work without rotating the tool at all, the projecting teeth bei close enough togetherl to effect the necessary breaking' up of the work-material. ln any case the need for rotating the tool may be slight, and will be partly dependent upon t ie extent of separation of the tcethor ribs 12 from one another; whereas in using the cross-shaped bit above mentioned, the same must be rotated to a 'great extent. in attempting to approximate a cylindrical form of hole in the work. `ll/loreover, these projecting teeth or ridges'12 between the flutes have the elfect of insuring accuracy of contour of the final hole 16 throughout its depth, so that a firm anchorage is afforded for the expansion bolt.

The provision of the teeth 12 secures the further advantage that the hole 16 can he made of precisely the required diameter within very close limits, so that holes may bev readily and practically produced for eX- pansion bolts of a given diameterA without' incurring liability, of their being unable to expand sufficiently to become anchored 1n the holes. lhe tool, inasmuch as it has the ainev diameter throughout, willmake holes same throughout the depth of the hole, thus i securing accuracy in diameterand shape of i hole throughout.

The even surface in the hole thatl ispr0- dd by the improved tool, is better adapteo. to the expansion bolt, as more surface Contact is afforded between the bolt and the hole, and the bolt is. tighter and firmer.

hioreover, the cement or other material stands up under the strain under which it `is put by the expansion bolt, because the strain is spread over a greater area, instead of being confined to `a few high points in an irregular hole, which might spread and cause the material to crack.

This tool is always sharp as well as always self-clearing, because there is always substantially the same amount of metal to sustain the blow. It does not necessarily have keen working edges or nilos, lout there is always substantially the same amount 0f working face at the nilo. Certain former drills became more blunt as they were operated, Vand therefore more surface was eX- posed to the blow, and hence less impression was made upon the work. But this improved tool can be worked until it is worn otl to the hilt, and it is always substantially the same.

The size of successive holes made in the cement or brick worm, or the like, is exactly the same until the drill is worn out. Each hole is true and of exactly the right diameter. l

The tool may be made of considerable length, so as to have a longlife, and secure 5, for certain other classes of work.

The hollow tool may have a set of teeth 12 only on its exterior, for certain classes of work, and may have similar teeth or ribs 19 only on the interior, Figures 4 pd or still other kinds of work, it may have both exterior andinterior iutes 11, 2O and teeth 12, 19, as at Figures 4 and'. The annular channel 16, 21, at Figure 5, is thus made a little wider than at Figure 2. l

The inside teeth 19 may serve to clear the hole in certain classes of work, so that packing does not take place. Where inside teeth arev provided, the work core or plug is ,reduced a little in diameter, and the operation is highly successful (whether outside teeth 12 are also used or not), and the clearing CJD is more satisfactory, the dust ispnot apt to cause the plug to stick in the tool, and th-e tool is more likely to fit ythework core loosely, and the latter is more readily shaken out, than Where the inside teeth are omitted. rlhe inside teeth 19 do not need to be deep, but just enough to make a clearance inside of the bore of the tool.

It will be seen that the expansion-boltsocket forming drill terminates in a series of chisel-edges impinging upon the work, each chisel-edge, as at Figure 5 preferably comprising two ribs 12, 19, and the intervening segmental wall-portion of the tool, said wall-portion being defined by the fluting 11. The'work-engaging portion of the tool consists of chisel-edges which are formed or defined by the perforations, the perforations extending in rows longitudinally of the tool, the rows being preferably straight, and the perforations having an echelon arrangement. By reason of this arrangement, the chisel-edges are divided into two sets, each set comprising rows of chisel-edges extending longitudinally of the tool, the rows of chisel-edges in one set alternating with the rows of chisel-edges in the other set. Upon the wearing away of the four chisel-edges in either set, they are suc-f ceeded bythe next four fresh chisel-edges in the other set.

At Figures 9 and 10 there is shown a point 23, which may be fitted inthe end of the drill to start the hole in the work. The point may be cross-shaped when viewed endwise, as shown, and the attachment may comprise this cross-shaped head and a shank 24 for insertion into the end of the tool,

which it fits tightly. After the hole is started by means of the pointed head, the

latter may be removed from the tool, and the hole then drilled in the manner hereinbefore explained.

The holes 13 in the tool 10 are preferably cylindrical and therefore .easy to make. In making these holes, the machine drill can rgo clear through the tool from one sidevto the other, thus making the two holes in the opposite sides of the tool 10 at one operation, with a symmetrical result. There is preferably an even number of similar flutes 11 for this reason,'and the expense is thereby reduced. The inside ilutings 2O K (where employed) coincide radially with the outside iiutings 11, so that the same holes 13 occur between both theinterior ribs 19 and -the exterior ribs 12. Y

The tool may be made of gas-piping or other tubing of either hard or soft steel, according to the nature of the work to be performed; and if made of soft steel it may be case-hardened, thus adding to the effi# ciency of the tool, such increased efficiency enduring until the entire tool is worn out. The tool may be formed with la head 22 and may be used with pneumatic drills, or otherwise.

Variations may be resorted to within the lsc'opefof the invention, and portions of the While the drawings show drills having. six

and eight sides or flutes, it will'be under stood that the invention is not limited to this number of sides. It is not in some cases desirable to have the perforations 13 spaced widely apart circumferentially ofthe drill, because it is not well to have too much edge or nib striking the work. In larger drills there may be more flutes or sides for certain kinds of work.

Having thus described my invention, I cla-im: y

1. A drill of the class' described, in the form of ahollow tool of the same diameter throughout and having aV self-renewing wearing edge or nib thin enough to produce having an echelon arrangement around the tool.

2. A drill of the class described, in the arrangement relatively to those in the adjoining rows. v Y

3. A drill of the class described, in the Y :torni of a hollow tool of the same-diameter throughout and having a self-renewing wearing edge or nib thin enough to produce a cut in the material when the tool is hammered and provided with straight longitudinal ribs at intervals around its periphery, the tool having rowsoi chisel-i'orming pertorations in echeon between the ribs7 said ribs being both exterior and interior, and the iiutes between the interior ribs coinciding substantially with those between the eX- terior ribs.

Ll. A. drill ot the class described, in the form ot a hollow tool of the same diameter throughout and having a self-renewing wearing edge or nib and provided with longitudinal ribsat intervals around its periphery, the tool having rows ot' perforations between the ribs, said ribs being both exterior and interior7 and the flutes between the interior ribs coinciding substantially with those between the exterior ribs, said periorations being cylindrical, and the flutes being evenly 'spaced and of an even number, the perforations in each tinte being opposite the perforat-ions in another flute.

5. A drill of the class described.l Vin the form of a. hollow tool of the same diameter throughout and having a self-renewing wearing edge or nib impinging directly upon the worlr to produce a cut therein when the tool is hammered and provided with longitudinal ribs at intervals around its periphery, the tool having rows of chisel-forming pert'orations in echelon arrangement between the ribs7 dividing said tool into longitudinal rows of chisel-points in echelon arrangement and forming sets which come alternately into use by reason of thefwearing away of the tool. f

6. A drill of the class described, in the form of a hollow tool of the same diameter throughout and having a self-renewing` wearing edge or nib impinging directly upon the work to produce a cut therein when the tool is hammered and provided with longitudinal ribs at intervals around its periphery, the tool having rows of chisel-forming perforations in echelon arrangement between the ribs, dividing said tool into longik tudinal rows of chisel-edges in echelon arrangement and forming sets which come alternately into use by reason of the wearin away of the tool, said tool being' case-hardened.-

7. A drill of the class described, in the form of a hollow 4tool 01"' the same diameter throughout and having a seit-renewing wearing edge or nib and provided with longitudinal ribs at intervals around its periphery, the tool having rows ot perforations between the ribs, said tool having a head secured thereto for hammering.

8. A drill ot the class described, in the form of a hollow tool o'l the same diameter 'throughout and having a self-renewing wearing edge or nib thin enough to produce a cut in the material when the tool is hammered and provided with longitudinal surface ribs for securing clearance, said ribs` being straight for the length of the tool, rows ot chisel-forming periorations between the ribs, dividing the tool into chisel-edges impinging directly upon the work, said periterations having an echelon arrangement.

9. A' drill in the torni of a hollow tool and having a self-renewing wearing edge or nib and provided with longitudinal surface ribs, and a pointed head inse-rtedupon the end et said tool tor starting a hole in the work; said head being removable. V

l0. A drill in the form et a hollow tool and having a Lself-renewing wearing edge or nib and provided with longitudinal suriace ribmand a pointed head inserted upon the end oiL said tool for starting a hole in the work; said pointed head .being crossshaped, as set forth, and having a shank portion for insertion into the end .of the tool.

ll. n eXpansion-bolt-soclet forming drill in a. form of a hollow tool of the same diameter throughout .its length and terminating in a series of chisel edges impinging upon the work-to produce a cut therein when the tool is hammered, said chisel .edges separated by chisel-forming perforated portions of said tool, the material of 4the tool between the per'torations constituting the chisel edges and being brought successively into use by the wearing away of the tool, said perforations having an echelon arrangement, and dividing the ltool into a succession of annular series of alternating chisel edges and spaces, the chisel edges being formed in columns upon said tool, and chisel edges in one set ot columns coming into use as those of alternating columns are worn away.

1Q. An expansion-bolt-socket forming drill. in a form olf a hollow tool of the saine diameter throughout its length and terminating in a series of chisel edges impinging upon the work to produce a cut therein when the tool is hammered, said chisel edges separated by chisel-forming perforated portions of saidy tool, the material ot the tool between thel aeriiorations constituting the chisel edges and being brought successively into use by the wearing away or' the tool, said perforations having an echelon arrangement, and dividing the tool into a succession of annular eries of alternating chisel edges and spaces the chisel edgesbeing formed in columns upon said tool, and chisel edges in one set of columns coming into use as those of alternating columns are worn away, said tool formed with ribs extendingl longitudinally thereof and forming portions of the chisel 'edges and securing clearance.

13. An eXpansion-bolt-socket forming drill llfl lill

in a itorm of ahollow tool of the same diameis hammered, said chisel edges separated by chisel-forming perforated portions of said tool, the material of the tool between the perforations constituting the chisel edges and being brought successively into use by the wearing away of the tool, said perforations having. an echelon arrangement, and dividing the tool into a succession of annular series of alternating chisel edges and spaces, the chisel edges being formed in columns upon said tool, and chisel edges in one set of columns coming into use as those oi". alternating columns are Worn away, said tool formed with ribs extending longitudinally thereof and forming portions of the chisel edges and securing clearance, said ribs extending parallel with the axis of the tool7 and said perforations disposed in rows between the ribs.

ADOLPH W. MACHLET. 

